The present invention relates to a new fluorocompound and surfactant to which can be imparted surface functions such as water repellency, oil repellency, grime resistance, and electrostatic resistance, and a water-based coating material and silver halide photographic light-sensitive material employing the same.
Compounds having fluoroalkyl chains are known as surfactants. Various surface property modifications can be conducted based on the unique properties (water repellency, oil repellency, lubricating property, electrostatic resistance, and the like) of fluoroalkyl chains, and they are widely employed in the surface processing of base materials such as fiber, cloth, carpet, and resins. Furthermore, not only can uniform films be formed without repelled spots during film formation when surfactants comprising fluoroalkyl chains (referred to hereinafter as fluorosurfactants) are added to aqueous medium solutions of various matrixes, but an adsorption layer of the surfactant can be formed on the matrix surface, imparting the above-mentioned unique properties of fluoroalkyl chains to the film surface.
Various surfactants are employed in photographic light-sensitive materials, performing important roles. Photographic light-sensitive materials are usually manufactured by applying multiple coating solutions comprising aqueous solutions of a hydrophilic colloidal binder (such as gelatin) on a support member to form multiple layers. Often, multiple hydrophilic colloidal layers are simultaneously applied in multiple layers. These layers include antistatic layers, undercoating layers, antihalation layers, silver halide layers, intermediate layers, filter layers, and protective layers. Various substances are added to individual layers to impart specific functions. Furthermore, polymer latex is sometimes incorporated into hydrophilic colloidal layers to improve the physical properties of the films. To incorporate highly water-insoluble functional groups such as color couplers, ultraviolet absorbing agents, fluorescent whitening agents, and lubricants into hydrophilic colloidal layers, these substances are sometimes dispersed and emulsified as is in hydrophilic colloidal solutions or as solutions of high-boiling-point organic solvents such as phosphoric ester compounds and phthalic ester compounds, and employed in the preparation of coating solutions. Generally, in this manner, photographic light-sensitive materials are comprised of various hydrophilic colloidal layers, and in the course of manufacturing, coating solutions comprising various substances are required to permit uniform high-speed coating without the drawbacks of repelled spots and coating irregularity. To fulfill such demands, surfactants are often added to coating solutions as adjuvants.
Additionally, photographic light-sensitive materials come into contact with a variety of substances during manufacturing, photographing, and developing. For example, during processing, when the light-sensitive material is wound up, the backing layer formed on the back surface of the support sometimes comes into contact with the front surface. Furthermore, in the course of conveying during processing, there is sometimes contact with stainless steel and rubber rollers. Upon contact with such materials, the surface of the light-sensitive material (gelatin layer) tends to develop a positive charge, sometimes causing unwanted discharge leaving behind undesirable exposure traces (known as static marks) on the light-sensitive material. Compounds comprising fluorine atoms are effective at reducing the electrostatic property of the gelatin, and fluorine surfactants are often added.
Thus, surfactants, particularly fluorine surfactants, are employed as materials functioning both as coating adjuvants imparting uniform properties to the coating film and as antistatic agents in the photographic light-sensitive material. Specific examples are disclosed in JP-A-49-46733, JP-A-51-32322, JP-A-57-654228, JP-A-64-536, JP-A-2-141739, JP-A-3-95550, and JP-A-4-248543 (the term xe2x80x9cJP-Axe2x80x9d as used herein means an xe2x80x9cunexamined published Japanese patent applicationxe2x80x9d). However, these materials do not necessarily afford satisfactory performance as regards demands for high sensitivity and high-speed coating in photographic light-sensitive materials of recent years, and further improvement in fluorine surfactants is needed. Generally, short perfluoroalkyl chains are considered advantageous from the viewpoint of decomposition (the decomposition of the compound following use), but the orientation of the fluoroalkyl chain in the coating surface decreases markedly. Accordingly, there is a strong need for the development of a fluorosurfactant with a relatively short fluoroalkyl chain affording both surface orientation (related to the electrostatic property) and coating uniformity.
The present invention has as its object to provide a new fluorocompound and a surfactant comprising the same that permit uniform film formation when employed during film formation while having short perfluoroalkyl groups. A further object of the present invention is to provide an aqueous coating composition capable of forming uniform films having antistatic properties. A still further object of the present invention is to provide a silver halide light-sensitive material imparted with antistatic properties while permitting stable production.
The foregoing objects are accomplished by the invention to provide a fluorocompound denoted by general formula (1) below. 
(wherein R1 denotes a substituted or unsubstituted alkyl group having a total of at least six carbon atoms, with R1 not being an alkyl group substituted with a fluorine atom; Rf denotes a perfluoroalkyl group having not more than six carbon atoms; either X1 or X2 denotes a hydrogen atom and the other denotes SO3M; M denotes a cation; and n denotes an integer of not less than 1).
In the formula (1), R1 preferably denotes a substituted or unsubstituted alkyl group with a total of 6-24 carbon atoms, more preferably, a substituted or unsubstituted alkyl group with a total of 6-18 carbon atoms, and further preferably, an unsubstituted alkyl group with a total of 8-10 carbon atoms.
In the formula (1), n preferably denotes an integer of 1-4, more preferably, 1 or 2.
In the formula (1), it is preferably that when n=1, Rf denotes a heptafluoro-n-propyl group or nonafluoro-n-butyl group, and when n=2, Rf denotes a nonafluoro-n-butyl group.
In the formula (1), M preferably denotes an alkali metal ion, alkali earth metal ion or ammonium ion.
This invention further provides a silver halide photographic light-sensitive material having at least one layer comprising a light-sensitive silver halide emulsion layer on a support and comprising a compound denoted by general formula (1) below in at least one layer thereof 
(wherein R1 denotes a substituted or unsubstituted alkyl group having a total of at least six carbon atoms, with R1 not being an alkyl group substituted with a fluorine atom; Rf denotes a perfluoroalkyl group having not more than six carbon atoms; either X1 or X2 denotes a hydrogen atom and the other denotes SO3M; M denotes a cation; and n denotes an integer of not less than 1).
In a preferred embodiment of the present invention, there is a light-insensitive hydrophilic colloidal layer in the outermost layer and said outermost layer comprises the compound denoted by said general formula (1).
In a preferred embodiment of the present invention, at least one of the silver halide emulsions comprised in said silver halide emulsion layers is an emulsion in which not less than 50 percent of the total projection area of the silver halide grains is made up of grains with an aspect ratio of not less than 3, in a more preferred, not less than 8.
In a preferred embodiment of the present invention, at least one of the silver halide comprised in said silver halide emulsion layers is iodobromide, iodochloride, bromochloride or iodochlorobromide.
In a preferred embodiment of the present invention, at least one of the silver halide emulsions comprised in said silver halide emulsion layers is subjected to at least one from among sulfur sensitization, selenium sensitization, gold sensitization, palladium sensitization, or noble metal sensitization
This invention further provides a surfactant and a water-based coating composition comprising a fluorocompound denoted by general formula (1) above.
The present invention is described in detail below. In the present Specification, the symbol xe2x80x9c-xe2x80x9d indicates a range having as minimum and maximum the two numbers before and after it, inclusive.
The fluorocompound and surfactant of the present invention will be described first. The fluorocompound of the present invention is denoted by general formula (1) below. The fluorocompound of the present invention may be employed as a surfactant.
In general formula (1), R1 denotes an alkyl group substituted with a total of six or more carbon atoms or unsubstituted. However, R1 does not denote an alkyl group substituted with a fluorine atom. The substituted or unsubstituted group denoted by R1 may have a straight-chain, branching chain, or ring structure. Examples of the above-mentioned substituents are alkylenyl groups, aryl groups, alkoxy groups, halogen atoms other than fluorine, carboxylic ester groups, carbonamide groups, carbamoyl groups, oxycarbonyl groups, and phosphoric ester groups.
The substituted or unsubstituted alkyl group denoted by R1 preferably has a total of 6-24 carbon atoms. Examples of unsubstituted alkyl groups having 6-24 carbon atoms are: n-hexyl groups, n-heptyl groups, n-octyl groups, tert-octyl groups, 2-ethylhexyl groups, n-nonyl groups, 1,1,3-trimethylhexyl groups, n-decyl groups, n-dodecyl groups, cetyl groups, hexadecyl groups, 2-hexyldecyl groups, octadecyl groups, eicosyl groups, 2-octyldodecyl groups, docosyl groups, tetracosyl groups, 2-decyltetradecyl groups, tricosyl groups, cyclohexyl groups, and cycloheptyl groups. Examples of preferred substituted alkyl groups with a total of 6-24 carbon atoms including the carbon atoms in the substituent are: 2-hexenyl groups, oleyl groups, linoleyl groups, linolenyl groups, benzyl groups, xcex2-phenethyl groups, 4-phenylbutyl groups, 6-phenoxyhexyl groups, 12-phenyldodecyl groups, 18-phenyloctadecyl groups, 12-(p-chlorophenyl)dodecyl groups, and 2-(phosphoric diphenyl)ethyl groups.
The substituted or unsubstituted alkyl group denoted by R1 desirably has a total of 6-18 carbon atoms. Preferred examples of unsubstituted alkyl groups having 6-18 carbon atoms are n-hexyl groups, cyclohexyl groups, n-heptyl groups, n-octyl groups, 2-ethylhexyl groups, n-nonyl groups, 1,1,3-trimethylhexyl groups, n-decyl groups, n-dodecyl groups, cetyl groups, hexadecyl groups, 2-hexyldecyl groups, octadecyl groups, and 4-tert-butylcyclohexyl groups. Furthermore, preferred examples of substituted alkyl groups having a total of 6-18 carbon atoms including the carbon atoms in the substituent are: phenethyl groups, 6-phenoxyhexyl groups, 12-phenyldodecyl groups, oleyl groups, linoleyl groups, and linolenyl groups. Of these, R1 is preferably an n-hexyl group, cyclohexyl group, n-heptyl group, n-octyl group, 2-ethylhexyl group, n-nonyl group, cyclohexyl group, n-heptyl group, n-octyl group, 2-ethylhexyl group, n-nonyl group, 1,1,3-trimethylhexyl group, n-decyl group, n-dodecyl group, cetyl group, hexadecyl group, 2-hexyldecyl group, octadecyl group, oleyl group, linoleyl group, or linolenyl group. Straight-chain, cyclic or branching chain unsubstituted alkyl groups having 8-16 carbon atoms are particularly preferred.
In above-recorded general formula (1), Rf denotes a perfluoroalkyl group having not more than six carbon atoms. Here, the term xe2x80x9cperfluoroalkyl groupxe2x80x9d means an alkyl group in which all the hydrogen atoms have been substituted with fluorine atoms. The alkyl group in the perfluoroalkyl group may have a straight-chain, branching chain, or ring structure. Examples of the perfluoroalkyl group denoted by Rf are trifluoromethyl groups, pentafluoroethyl groups, heptafluoro-n-propyl groups, heptafluoroisopropyl groups, nonafluoro-n-butyl groups, undecafluoro-n-pentyl groups, tridecafluoro-n-hexyl groups, and undecafluorocyclohexyl groups. Of these, perfluoroalkyl groups having 2-4 carbon atoms (for example, pentafluoroethyl groups, heptafluoro-n-propyl groups, heptafluoroisopropyl groups, and nonafluoro-n-butyl groups) are preferred, and heptafluoro-n-propyl groups and nonafluoro-n-butyl groups are particularly preferred.
In above-recorded general formula (1), n denotes an integer of not less than 1, preferably 1-4, and more preferably, 1 or 2.
Furthermore, in combinations of n and Rf, when n=1, Rf is preferably a heptafluoro-n-propyl group or nonafluoro-n-butyl group, and when n=2, Rf is preferably a nonafluoro-n-butyl group.
In above-recorded general formula (1), either X1 or X2 denotes a hydrogen atom and the other denotes SO3M, where M denotes a cation. Here, preferred examples of the cation denoted by M are alkali metal ions (lithium ion, sodium ion, potassium ion, or the like), alkaline earth metal ions (barium ion, calcium ion, or the like), and ammonium ions. Of these, the most preferred are lithium ions, sodium ions, potassium ions, and ammonium ions.
Specific preferred examples of the fluorocompound denoted by above-recorded general formula (1) are given below; however, the present invention is in no way limited to these specific examples. For simplicity, in the examples of the compounds given below, X1 denotes SO3M and X2 denotes a hydrogen atom. But X1 can also denote a hydrogen atom and X2 can denote SO3M in the examples of compounds given below, and those compounds are also specific examples of the fluorocompound of the present invention.
In the structural annotation of the examples of compounds given below, unless specifically stated otherwise, a perfluoroalkyl group means a straight-chain structure. In the abbreviated structural annotation below, groups having the symbols 2EH and 2BO comprise the following groups, respectively:
2EH: 2-ethylhexyl,
2BO: 2-butyloctyl. 
The fluorocompound denoted by above-recorded general formula (1) can be readily synthesized by combination of the usual esterification and sulfonation reactions.
The fluorocompound of the present invention is preferably employed as a surfactant in the various coating compositions for forming layers comprising recording materials (particularly silver halide photographic light-sensitive materials). Use in the formation of the hydrophilic colloid layer of the uppermost layer of the photographic light-sensitive material is particularly desirable in that it yields effective antistatic capability and coating uniformity. Coating compositions incorporating the fluorocompound of the present invention as surfactant are described below.
The water-based coating composition of the present invention comprises the surfactant of the present invention and a solvent in which the surfactant of the present invention is dissolved and/or dispersed. Other components may be appropriately incorporated as needed based on the objective.
An aqueous medium is preferred as the medium in the water-based coating composition of the present invention. Aqueous media include water and mixed solvents of water and organic solvents other than water (for example, methanol, ethanol, isopropyl alcohol, n-butanol, methyl cellosolve, dimethyl formamide, and acetone). In the present invention, the medium of the coating composition desirably comprises not less than 50 mass percent water.
One type of the fluorocompound of the present invention may be employed singly, or two or more types may be mixed and used in the water-based coating composition of the present invention. Other surfactants may also be employed with the fluorocompound of the present invention. Examples of other surfactants suitable for use in combination are various anionic, cationic, and nonionic surfactants. The surfactants employed in combination may be macromolecular surfactants or fluorine surfactants other than the surfactant of the present invention. Anionic or nonionic surfactants are preferred as the surfactants employed in combination. Examples of surfactants suitable for use in combination are those described in JP-A-62-215272 (pp. 649-706), Research Disclosure (RD) Item 17643, pp. 26-27 (December, 1978), RD Item 18716, p. 650 (November 1979), and RD Item. 307105, pp. 875-876 (November, 1989).
Polymer compounds are representative examples of other components that can be incorporated into the water-based coating composition of the present invention. The polymer compounds may be soluble in aqueous media (referred to hereinafter as xe2x80x9csoluble polymersxe2x80x9d) or polymer-in-water dispersions (known as xe2x80x9cpolymer latexesxe2x80x9d). Soluble polymers are not specifically limited; examples are: gelatin, polyvinyl alcohols, casein, agar, gum arabic, hydroxyethyl cellulose, methyl cellulose, and carboxymethyl cellulose. Examples of polymer latexes are homopolymers and copolymers of various vinyl monomers (for example, acrylate derivatives, methacrylate derivatives, acrylamide derivatives, methacrylamide derivatives, styrene derivatives, conjugate diene derivatives, N-vinyl compounds, O-vinyl compounds, vinylnitrile, and other vinyl compounds (such as ethylene and vinylidene chloride)) and dispersions of condensation polymers (such as polyester, polyurethane, polycarbonate, and polyamide). Examples of specific polymer compounds of this type are the polymer compounds described in JP-A-62-215272 (pp. 707-763), RD Item 17643, p. 651 (December, 1978), RD Item 18716, p. 650 (November 1979), and RD Item. 307105, pp. 873-874 (November, 1989).
Other types of compounds may be incorporated into the water-based coating composition of the present invention, or they may be dissolved or dispersed in a medium. For example, when employed in the formation of the structural layers of a photographic light-sensitive material, examples are various couplers, ultraviolet-absorbing agents, anticolor mixing agents, antistatic agents, scavengers, antifogging agents, film-hardening agents, dyes, and antimildew agents. Furthermore, as set forth above, the water-based coating composition of the present invention is desirably employed in the formation of the hydrophilic colloid layer of the uppermost layer of photographic light-sensitive materials. In that case, other surfactants, matting agents, lubricants, colloidal silica, gelatin plasticizers, and the like may be incorporated into the coating composition in addition to a hydrophilic colloid (gelatin, for example) and the fluorine composition of the present invention.
The quantity employed of the fluorocompound of the present invention is not specifically limited. However, the quantity employed may be freely determined based on the structure and use of the compound employed, the type and quantity of the substances incorporated into the water-based composition, the structure of the medium, and the like. For example, when employing the water-based coating composition of the present invention as the coating solution for the hydrophilic colloid (gelatin) layer of the uppermost layer of a silver halide photographic light-sensitive material, the concentration in the coating composition of the fluorocompound of the present invention is desirably 0.003-0.5 mass percent, and preferably 0.03-5 mass percent based on the gelatin solid component.
The silver halide photographic light-sensitive material of the present invention is characterized in that at least one layer comprising a light-sensitive silver halide emulsion layer is present on a support and the fluorocompound of the present invention is incorporated into at least one layer. As an example of a preferred implementation mode of the silver halide photographic light-sensitive material of the present invention, there is a light-insensitive hydrophilic colloid layer as the outermost layer and this outermost layer comprises the fluorocompound of the present invention.
The silver halide photographic light-sensitive material of the present invention can be manufactured by coating one or more of the water-based coating compositions of the present invention on a support. The method of applying the coating composition is not specifically limited, it being possible to employ a slide bead coating method, slide curtain coating method, extrusion curtain coating method, or extrusion bead coating method. Of these, the slide bead coating method is preferred.
Various materials employed in the silver halide photographic light-sensitive material of the present invention will be described below in an example of a silver halide color photographic light-sensitive material.
Silver halide grains suited to use in the silver halide photographic light-sensitive material of the present invention may be in the form of regular cubic, octahedral, or tetrakaidecahedral crystals, irregular spherical or platelike crystals, crystals having twin-plane or other crystalline defects, or combinations of the same. Platelike grains are particularly preferred.
In platelike granular emulsions, more than 50 percent of the total projected area is desirably made up of grains with an aspect ratio of not less than three. The projected area and aspect ratio of the platelike grains referred to here can be measured in electron microscope photographs by the carbon replica method in which shadows are cast together with reference latex spheres. When the platelike grains are viewed in a direction perpendicular to the main plane, they are usually hexagonal, triangular, or round in form. The value obtained by dividing the diameter (circle equivalent diameter) corresponding to a circle of area equal to the projected area by the thickness is the aspect ratio. The higher the ratio of hexagonally shaped platelike grains the better, and the ratio of the length of adjacent hexagonal edges is desirably not greater than 1:2.
As regards the effect of the present invention, since better photographic performance is achieved the higher the aspect ratio, not less than 50 percent of the total projected area of the platelike granular emulsion is desirably comprised of grains with an aspect ratio of not less than 8, preferably not less than 12. Since the greater the aspect ratio, the higher the variation coefficient of grain size distribution tends to become, an aspect ratio of not less than 50 is normally desirable.
The mean grain diameter of the silver halide grains is desirably 0.2-10.0, xcexcm, more preferably 0.5-5.0 xcexcm, as a mean circle equivalent diameter. The term xe2x80x9cmean circle equivalent diameterxe2x80x9d means the diameter of a circle having an area equal to the projected area of the parallel main surface of the grain. The projected area of the grain is measured as the area on an electron microscope photograph corrected for photographic magnification. As a mean sphere equivalent diameter, the diameter is desirably 0.1-5.0 xcexcm, preferably 0.6-2.0 xcexcm. These ranges yield photographic emulsions with the best relation of sensitivity/grain shape ratio.
For platelike grains, an average thickness of 0.05-1.0 xcexcm is desirable. The term average circle equivalent diameter referred to here is the average value of the circle equivalent diameter of not fewer than 1,000 grains collected at random in a uniform emulsion. This is also true for the average thickness.
The silver halide grains may be in the form of a monodispersion or polydispersion.
The platelike grain emulsion desirably comprises the opposing (111) main planes and the lateral planes connected to these main planes. At least one twin plane surface is desirably present between the main planes. Normally, two twin planes are desirably observed in the platelike grain emulsion employed in the present invention. The gap between the two twin planes can be made less than 0.012 xcexcm as described in U.S. Pat. No. 5,219,720. Furthermore, the value of the distance between main planes (111) divided by the gap between the twin planes can be made 15 or greater as described in JP-A-5-249585. In the present invention, not more than 75 percent of the total lateral planes connecting opposing main planes (111) of the platelike grain emulsion are desirably comprised of planes (111). Here, the statement that not more than 75 percent are comprised of planes (111) means that crystallographic planes other than the (111) planes are present in a ratio of greater than 25 percent of the total lateral planes. It will be understood that these planes are normally the (100) planes, but cases where they are some other plane, such as the (110) plane or a plane with a higher index, are also included. The effect of the present invention decreases markedly when less than 70 percent of the total lateral planes are comprised of plane (111).
Examples of silver halide solvents suitable for use in the present invention are (a) the organic thioethers described in U.S. Pat. Nos. 3,271,157, 3,531,289, and 3,574,628 and JP-A-54-1019, Sho 54-158917; (b) the thiourea derivatives described in JP-A-53-82408, JP-A-55-77737 and JP-A-55-2982; (c) the silver halide solvents having thiocarbonyl groups incorporating oxygen or sulfur atoms and nitrogen atoms described in JP-A-53-144319; (d) the imidazoles described in JP-A-54-100717; (e) ammonia; and (f) thiocyanates.
Solvents of particular preference are thiocyanate, ammonia, and tetramethylthiourea. The quantity of solvent employed varies by type, but in the case of thiocyanate, is preferably 1xc2x710xe2x88x924 mol to 1xc2x710xe2x88x922 mol per mol of silver halide.
European Patent No. 515894A1 can be referred to for the method of changing the plane index of the lateral planes of the platelike grain emulsion. The polyalkylene oxide compound described in U.S. Pat. No. 5,252,453 can also be employed. The plane index modifying agents described in U.S. Pat. Nos. 4,680,254, 4,680,255, 4,680,256, and 4,684,607 may also be employed as effective methods. Commonly employed photographic spectral sensitization pigments may also be employed as plane index modifiers similar to those set forth above.
So long as they satisfy the above-stated requirements, the silver halide emulsion can be prepared by a variety of methods. Normally, preparation of the platelike grain emulsion comprises the three basic steps of nucleation, maturation, and growth. In the nucleation step, the use of the gelatin comprising a small quantity of methionine described in U.S. Pat. Nos. 4,713,320 and 4,942,120; the conducting of nucleation with high pBr described in U.S. Pat. No. 4,914,014; and the conducting of nucleation in a short period as described in JP-A-2-222940 are extremely effective in the nucleation step of the platelike grain emulsion employed in the present invention. The conducting of maturation in the presence of a low-concentration base described in U.S. Pat. No. 5,254,453 and the conducting of maturation at high pH described in U.S. Pat. No. 5,013,641 are useful in the step of maturing the platelike grain emulsion. The conducting of growth at low temperature described in U.S. Pat. No. 45,248,587 [sic] and the use of silver iodide micrograins described in U.S. Pat. Nos. 4,672,027 and 4,693,964 are particularly effective in the growth step of the platelike grain emulsion. It is also desirable to conduct growth through maturation by adding silver bromide, silver iodobromide, and silver chloroiodobromide micrograin emulsions. It is also possible to feed the above-listed micrograin emulsions with the stirring device described in JP-A-10-43570.
The silver halide emulsion is desirably silver iodobromide, iodochloride, bromochloride, or iodochlorobromide. It is preferably comprised of silver iodobromide or iodochlorobromide. In the case of iodochlorobromide, silver chloride may also be incorporated, but the silver chloride content is desirably not more than 8 molar percent, preferably not more than 3 molar percent, or even 0 molar percent. Since the variation coefficient of the grain size distribution is desirably not greater than 25 percent, the silver iodide content is desirably not greater than 20 molar percent. Reducing the silver iodide content facilitates a reduction in the variation coefficient of the grain size distribution of the platelike grain emulsion. A variation coefficient in grain size distribution in the platelike grain emulsion of not greater than 20 percent and a silver iodide content of not greater than 10 molar percent are particularly desirable. Irrespective of the silver iodide content, a variation coefficient of the distribution of the silver iodide content between grains of not greater than 20 percent is desirable, and not greater than 10 percent is preferred.
With regard to the silver iodide distribution, the silver halide emulsion preferably has an intragranular structure. In that case, the structure of the silver iodide distribution can be a double structure, triple structure, quadruple structure, or structure of some higher order.
For example, the structure of the silver halide emulsion is desirably a triple structure grain comprising silver bromide, silver iodide, and silver bromide, or a higher order structure. The boundary of the silver iodide content between structures can be sharp or change continuously and gradually. Normally, measurement of the silver iodide content by powder X-ray diffraction does not reveal two sharp peaks of differing silver iodide contents, but an X-ray diffraction profile trailing in the direction of high silver iodide content.
It is further desirable for the silver iodide content in the phase on the inside to be higher than the silver iodide content on the surface. The silver iodide content of the phase on the inside is desirably at least 5 molar percent, preferably at least 7 molar percent, higher than that of the surface.
When the silver halide emulsion comprises platelike grains, the platelike grains have a dislocation line. The dislocation line of platelike grains can be observed, for example, by the direct method employing a transmission electron microscope at low temperature described by J. F. Hamilton, Phot. Sci. Eng., 11, 57, (1967), and T. Shiozawa, J. Soc. Phot. Sci. Japan, 35, 213 (1972). That is, silver halide grains removed from the emulsion while being careful not to apply pressure of a degree that would generate a dislocation line in the grains are placed on a mesh used for electron microscope observation, and while cooling the sample to prevent damage (printout and the like) by the electron beam, the sample is observed by transmission. At that time, the thicker the grains, the less the tendency for the electron beam to pass through. Thus, clear observation is possible by a method employing high-voltage (not less than 200 kV for grains with a thickness of 0.25 xcexcm) electron microscopy. From photographs of grains obtained by such methods, it is possible to calculate the position and number of dislocation lines for each grain when viewed from a direction perpendicular to the main plane.
The number of dislocation lines is preferably an average of not fewer than ten per grain, more preferably an average of not fewer than 20 per grain. When dislocation lines are densely present, or when mutually intersecting dislocation lines are observed, there are times when it is impossible to clearly count the number of dislocation lines per grain. However, in such cases, it is possible to make a rough count of degree as to whether there are 10 lines, 20 lines, or 30 lines, and make a clear distinction from the case where there are only several lines. The average number of dislocation lines per grain is counted for at least 100 grains and the average is calculated.
The silver halide grains may be subjected to at least one from among sulfur sensitization, selenium sensitization, gold sensitization, palladium sensitization, or noble metal sensitization at any time during the silver halide emulsion manufacturing process. Two or more sensitization methods are desirably employed in combination. Various types of emulsion can be prepared based on whether chemical sensitization is employed and when. There are types where a chemically sensitized nucleus is embedded within the grain, a type where it is buried at a shallow position from the grain surface, and a type where a chemically sensitized nucleus is formed on the surface. Chemically sensitized nuclei can be formed at desired spots based on the conditions used to prepare the emulsion on the basis of the objective. However, it is desirable to form at least one chemically sensitized nucleus near the surface.
One example of a preferred chemical sensitization that can be implemented is chalcogenide sensitization and noble metal sensitization, which can be employed singly or in combination. These chemical sensitizations can be conducted with an active gelatin such as described by T. H. James in The Theory of the Photographic Process, 4th ed., Macmillan, 1977, pp. 67-76, and combined with the sulfur, selenium, tellurium, gold, platinum, palladium, indium, or a combination of multiple members of this group of sensitizing agents at pAg 5-10, pH 5-8, and a temperature of 30-80xc2x0, described in Research Disclosure, Vol. 120, April, 1974, 12008; Research Disclosure, Vol. 34, June, 1975, 13452; U.S. Pat. Nos. 2,642,361, 3,297,446, 3,772,031, 3,857,711, 3,901,714, 4,266,018, and 3,904,415; British Patent No. 1,315,755. Salts of gold, platinum, palladium, indium, and other noble metals may be employed in noble metal sensitization, of which gold sensitization, palladium sensitization, and the combination of the two are preferred.
In the case of gold sensitization, known compounds such as auric chloride, potassium chloroaurate, potassium aurothiocyanate, gold sulfide, gold selenide, and other known compounds can be employed. In palladium sensitization, secondary and quaternary salts of palladium can be employed. Preferred palladium compounds for use in palladium sensitization are the compounds denoted by R2PdX6 and R2PdX4. Here, R denotes a hydrogen atom, alkali metal atom, or ammonium group. X denotes a halogen atom (chlorine, bromine, or iodine atom). Specific examples are K2PdCl4, (NH4)2PdCl6, Na2PdCl4, (NH4)2PdCl4, Li2PdCl4, Na2PDCl6, and K2PdBr4. Gold compounds and palladium compounds are desirably employed in combination with thiocyanates or selenocyanates.
Sulfur sensitization agents suitable for use are hypo- and thiourea compounds, rhodanine compounds, and the sulfur-containing compounds described in U.S. Pat. Nos. 3,857,711, 4,266,018, and 4,054,457. Chemical sensitization can also be conducted in the presence of a chemical sensitization adjuvant. Useful chemical sensitization adjuvants are compounds known to inhibit fogging in the chemical sensitization process and increase sensitivity, such as azaindene, azapyridazine, and azapyrimidine. Examples of chemical sensitization adjuvant modifying agents are described in U.S. Pat. Nos. 2,131,038, 3,411,914, and 3,554,757; JP-A-58-126526; and above-cited Duffin, Photographic Emulsion Chemistry, pp. 138-143.
Gold sensitization is desirably employed in combination in the silver halide emulsion. The preferred quantity of gold sensitizing agent is 1xc2x710xe2x88x924xe2x88x921xc2x710xe2x88x927 mol, more preferably 1xc2x710xe2x88x925xe2x88x925xc2x710xe2x88x927 mol, per mol of silver halide. The preferred quantity of palladium compound is 1xc2x710xe2x88x923xe2x88x925xc2x710xe2x88x927 mol per mol of silver halide. The preferred quantity of thiocyanate compounds and selenocyanate compounds is 5xc2x710xe2x88x922xe2x88x921xc2x710xe2x88x926 mol per mol of silver halide. The preferred quantity of sulfur sensitizing agent employed for silver halide grains is 1xc2x710xe2x88x924xe2x88x921xc2x710xe2x88x927 mol, preferably 1xc2x710xe2x88x9255xc2x710xe2x88x927 mol, per mol of silver halide.
Selenium sensitization is a desirable method of sensitizing the silver halide emulsion. Known unstable selenium compounds are employed in selenium sensitization. Specific examples of selenium compounds suitable for use are colloidal metallic selenium, selenoureas (for example, N,N-dimethylselenourea and N,N-diethylselenourea), selenoketones, and selenoamides. Selenium sensitization is desirably employed in combination with either or both of sulfur sensitization and noble metal sensitization. For example, thiocyanates are desirably added prior to the addition of the above-described spectral sensitization pigments and chemical sensitizing agents. More preferably, they are added after grain formation, and still more preferably, after the end of the desalting step. During chemical sensitization, it is also desirable to add thiocyanates. That is, during the chemical sensitization step, it is desirable to add thiocyanates at least twice. Examples of thiocyanates suitable for use are potassium thiocyanate, sodium thiocyanate, and ammonium thiocyanate. Thiocyanates are usually dissolved in an aqueous solution or a water-soluble solvent and added. The quantity added is 1xc2x710xe2x88x925xe2x88x9210xe2x88x922 mol, preferably 5xc2x710xe2x88x925xe2x88x925xc2x710xe2x88x923 mol, per mol of silver halide.
Gelatin is usefully employed as a protective colloid during preparation of silver halide emulsions and as a binder in other hydrophilic colloid layers. However, other hydrophilic colloids may also be employed. For example, it is also possible to employ gelatin derivatives, graft polymers of gelatin and other polymers, albumin, casein, and other proteins; hydroxyethyl cellulose, carboxymethyl cellulose, cellulose sulfuric esters, and other cellulose derivatives, sodium alginate, starch derivatives, and other sugar derivatives; polyvinyl alcohols, polyvinyl alcohol partial acetals, polyvinyl imidazoles, polyvinyl pyrazoles, and various other homopolymeric and copolymeric synthetic hydrophilic macromolecular substances.
In addition to lime-treated gelatins, acid-treated gelatins and enzyme-treated gelatins such as those described in Bull. Soc. Sci. Photo. Japan. No. 16, p. 30 (1966) may also be employed, as well as hydrolysis products of gelatins and enzyme decomposition products of gelatins.
After washing the emulsion obtained to remove salt, it is desirably dispersed again in a protective colloid. The temperature at which water washing is performed may be selected based on the objective, but the selection is desirably made-within a range of 5-50xc2x0 C. The pH during water washing may be selected based on the objective, but the selection is desirably made within a range of 2-10, and preferably 3-8. The pAg during water washing may be selected based on the objective, but the selection is desirably made within a range of 5-10. The method of water washing may be selected from among the noodle washing method, dialysis using a semipermeable membrane, centrifugation, coagulation and settling, and ion exchange. In coagulation and settling, a selection can be made among methods employing sulfates, methods employing organic solvents, methods employing water-soluble polymers, methods employing gelatin derivatives, and the like.
During emulsion preparation, for example, during grain formation, desalting, chemical sensitization, and prior to coating, the presence of metallic ion salts is desirable based on the objective. Addition during grain formation is desirable in cases where the grains are doped and addition after grain formation and before completion of chemical sensitization is desirable when employed to modify the grain surface or as chemical sensitizing agents. The entire grain may be doped, or only the grain core, grain shell, or epitaxial portion, or base grains may be doped. Examples of metallic ions that are suitable for use are Mg, Ca, Sr, Ba, Al, Sc, Y, LaCr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ru, Rh, Pd, Re, Os, Ir, Pt, Au, Cd, Hg, Tl, In, Sn, Pb, and Bi. These may be added in the form of ammonium salts, acetates, nitrates, sulfates, phosphates, hydroxides, hexadentate complexes, tetradentate complexes, and other salts that can be dissolved during grain formation. Examples are CdBr2, CdCl2, Cd(NO3)2, Pb(NO3)2, Pb(CH3COO)2, K3[Fe(CN)6], (NH4)4[Fe(CN)6], K3IrCl6, (NH4)3RhCl6, and K4Ru(CN)6. The ligands of coordination compounds may be selected from among halo, aquo, cyano, cyanate, thiocyanate, nitrosyl, thionitrosyl, oxo, and carbonyl ligands. These metallic compounds may be employed singly or in combinations of two, three, or more.
The metallic compounds are desirably dissolved in water, methanol, acetone, or some other suitable solvent for addition. The method of adding a hydrogen halide aqueous solution (such as HCl or HBr) or an alkali halide (such as KCl, NaCl, KBr, and NaBr) may be employed to stabilize the solution. As needed, an acid or alkali may also be added. The metallic compound may be added to the reaction vessel prior to or during grain formation. Alternatively, it may be added to a water-soluble silver salt (such as AgNO3) or an alkali halide water-soluble salt (such as NaCl, KBr, KI), and added continuously during silver halide grain formation. Furthermore, a solution separate from the water-soluble silver salt and alkali halide may be prepared and continuously added at the appropriate time during grain formation. The combination of various addition methods is also desirable.
There are also cases in which adding a chalcogenide compound such as described in U.S. Pat. No. 3,772,031 during preparation of the emulsion is effective. In addition to S, Se, and Te, the incorporation of cyanates, thiocyanates, selenocyanates, carbonates, phosphates, and acetates is also acceptable.
The use of an oxidizing agent for silver during the process of manufacturing the emulsion is desirable. However, silver nuclei imparting improved sensitivity achieved through reduction sensitization of the grain surface must remain to a certain degree. In particular, compounds converting to silver ions the extremely minute silver grains produced as by-products in the silver halide grain formation step and chemical sensitization step are effective. The silver ions produced here may form silver salts that are little soluble in water, such as silver halides, silver sulfides, and silver selenide, or may form silver salts that are readily soluble in water, such as silver nitrate.
Preferred oxidizing agents are inorganic oxidizing agents such as thiosulfonates and organic oxidizing agents such as quinones.
To prevent fogging during the process of manufacturing, storing, or photographically processing the light-sensitive material, or to stabilize the photographic properties thereof, various compounds may be incorporated into the photographic emulsion employed in the present invention. Numerous compounds known to be antifogging agents and stabilizers may be added, such as thiazoles in the form of benzothiazolium salt, nitroimidazole salt, nitrobenzimidazole salt, chlorobenzimidazole salt, bromobenzimidazole salt, mercaptothioazoles, mercaptobenzothiazoles, mercaptobenzimidazoles, mercaptothiadiazoles, aminotriazoles, benzotriazoles, nitrobenzotriazoles, mercaptotetrazoles, (particularly 1-phenyl-5-mercaptotetrazoles); mercaptopyrimidines; mercaptotriazines; thioketo compounds such as oxadolinethione; azaindenes such as triazaindenes, tetraazaindenes (particularly 4-hydroxy-substituted (1,3,3a,7)tetraazaindenes), and pentaazaindenes. The compounds described in U.S. Pat. Nos. 3,954,474 and 3,982,947 and in JP-A-52-28660 may be employed. One preferred compound is that described in JP-B-07-78597 (the term xe2x80x9cJP-Bxe2x80x9d as used herein means an xe2x80x9cexamined published Japanese patent applicationxe2x80x9d). Antifogging agents and stabilizers may be added at various times based on the objective, such as before grain formation, during grain formation, after grain formation, during the water washing step, during dispersion following water washing, before chemical sensitization, during chemical sensitization, after chemical sensitization, and before coating. In addition to adding these compounds during emulsion preparation to achieve the original effects of preventing fogging and stabilizing, they may also be added to control the crystal walls of the grains, reduce the size of the crystals, reduce the solubility of the crystals, control chemical sensitization, and control pigment disposition.
Layer arrangements, silver halide emulsions, dye formation couplers, functional couplers such as DIR couplers, various additives, and development usable in emulsions and photosensitive materials using the emulsions are described in European Patent No. 0565096A1 (laid open in Oct. 13, 1993) and the patents cited in it, the disclosures of which are herein incorporated by reference. The individual items and the corresponding portions are enumerated below.
1. Layer arrangements: p. 61(ll. 23-35, pp. 61(l. 41)-62(l. 14)
2. Interlayers: p. 61(ll. 36-40)
3. Interlayer effect donor layers: p. 62(ll. 15-18)
4. Halogen compositions of silver halide: p. 62(ll. 21-25)
5. Crystal habits of silver halide: p. 62(ll. 26-30)
6. Size of silver halide grains: p. 62(ll. 31-34)
7. Methods of emulsion preparation: p. 62(ll. 35-40)
8. Size distribution of silver halide grains: p. 62(ll. 41-42)
9. Tabular grains: p. 62(ll. 43-46)
10. Internal structures of grains: p. 62(ll. 47-53)
11. Latent image formation types of emulsions: pp. 62(l. 54)-63(l. 5)
12. Physical ripening-chemical ripening of emulsions: p. 63(ll. 6-9)
13. Usage of emulsion mixtures: p. 63(ll. 10-13)
14. Fogged emulsions: p. 63(ll. 14-31)
15. Non-light-sensitive emulsions: p. 63(ll. 32-43)
16. Silver coating amount: p. 63(ll. 49-50)
17. Photographic additives: described in Research Disclosure (RD) Item 17643 (December, 1978), RD Item 18716 (November, 1979), and RD Item 307105 (November, 1989), the disclosures of which are herein incorporated by reference. The individual items and the corresponding portions are presented below.
18. Formaldehyde scavengers: p. 64(ll. 54-57)
19. Mercapto-based antifoggants: p. 65(ll. 1-2)
20. Releasing agents, e.g. fogging agent: p. 65(ll. 3-7)
21. Dyes: p. 65(ll. 7-10)
22. General color couplers: p. 65(ll. 11-13)
23. Yellow, magenta, and cyan couplers: p. 65(ll. 14-25)
24. Polymer couplers: p. 65(ll. 26-28)
25. Diffusing dye forming couplers: p. 65(ll. 29-31)
26. Colored couplers: p. 65(ll. 32-38)
27. General functional couplers: p. 65(ll. 39-44)
28. Bleaching accelerator release couplers: p. 65(ll. 45-48)
29. Development accelerator release couplers: p. 65(ll. 49-53)
30. Other DIR couplers: pp. 65(l. 54)-66(l. 4)
31. Coupler diffusing methods: p. 66(ll. 5-28)
32. Antiseptic and antifungal agents: p. 66(ll. 29-33)
33. Types of light-sensitive materials: p. 66(ll. 34-36)
34. Light-sensitive layer film thickness and swell speed: pp. 66(l. 40)-67(l. 1)
35. Back layers: p. 67(ll. 3-8)
36. General development processing: p. 67(ll. 9-11)
37. Developers and developing agents: p. 67(ll. 12-30)
38. Developer additives: p. 67(ll. 31-44)
39. Reversal processing: p. 67(ll. 45-56)
40. Processing solution aperture ratio: pp. 67(l. 57)-68(l. 12)
41. Development time: p. 68(ll. 13-15)
42. Bleach-fix, bleaching, and fixing: pp. 68(l. 16)-69(l. 31)
43. Automatic processor: p. 69(ll. 32-40)
44. Washing, rinsing, and stabilization: pp. 69(l. 41)-70(l. 18)
45. Replenishment and reuse of processing solutions: p. 70(ll. 19-23)
46. Incorporation of developing agent into light-sensitive material: p. 70(ll. 24-33)
47. Development temperature: p. 70(ll. 34-38)
48. Application to film with lens: p. 70(ll. 39-41)
It is also possible to use a bleaching solution, described in European Patent No. 602600, which contains 2-pyridinecarboxylic acid or 2,6-pyridinedicarboxylic acid, ferric salt such as ferric nitrate, and persulfate. When this bleaching solution is to be used, it is preferable to carry out a stop step and a washing step between the color development step and the bleaching step, and use organic acid such as acetic acid, succinic acid, or maleic acid as the stop solution. Furthermore, for the purposes of pH adjustment and bleaching fog, the bleaching solution preferably contains 0.1 to 2 mols/litter (litter will be referred to as xe2x80x9cLxe2x80x9d hereinafter) of organic acid such as acetic acid, succinic acid, maleic acid, glutaric acid, or adipic acid.